Free power gas turbine engine with aerodynamic torque converter drive

ABSTRACT

A gas turbine engine including a first turbine stage and a second turbine stage, the first turbine stage being connected directly to the compressor and the second turbine stage being unconnected thereto, combined with an aerodynamic torque converter. The aerodynamic torque converter has an input shaft connected to the second stage of the turbine and an output shaft which can be selectively connected to the second stage of the turbine to provide for drive thru the aerodynamic torque converter or through the turbine and bypassing the aerodynamic torque converter.

Ullltfid States Patent 1 1 Hill 14 1 May 8, 1973 [54] FREE POWER GASTURBINE ENGINE 3,626,692 12 1971 Kumm ..60/39.l6 R WITH AERODYNAMICTORQUE 3,043,162 7/1962 Kugel et al.. ..74 720 CONVERTER DRIVE $331 1?311393 231;; 25752 12 3 [75] Inventor: Charles G. Hill, La Jolla, Calif.2:793:019 5/1957 Baumann ..60/39.l8 C

[73] Asslgnee: ga z gifi zfiy h Corporatlon Primary Examiner-Carlton R.Croyle 00m i Assistant Examiner-Warren Olsen [22] Filed: Dec. 29, 1971Attorney-Barnes, Kisselle, Raish & Choate [21] Appl. No.: 213,437 [57]ABSTRACT A gas turbine engine including a first turbine stage and [52]"60/3916 4 1 13 6 a second turbine stage, the first turbine stage being1 51 I Cl F 2 2 connected directly to the compressor and the second 0 tb e Stage being con o comb 1e 0 care /39.l6i, 4, with an aerodynamictorque converter. The

60/39'18 74/720 aerodynamic torque converter has an input shaftconnected to the second stage of the turbine and an out [56] ReferencesC'ted put shaft which can be selectively connected to the UNITED STATESPATENTS second stage of the turbine to provide for drive thru Y theaerodynam1c torque converter or through the tur- 3,314,232 4/1967 Hill..60/39.24 bine and bypassing the aerodynamic torque converter.3,587,766 6/1971 Slade ..60/39.l8 C 2,374,510 4/1945 Traupel ..60/39.l8C 4 Claims, 2 Drawing Figures This invention relates to gas turbineengines and particularly to the output due of a gas turbine engine forproviding work.

BACKGROUND OF THE INVENTION In the United States patent to Charles C.Hill US. Pat. No. 3,314,232, there is disclosed and claimed a gasturbine engine coupled with an aerodynamic torque converter whereincompressible fluid from the compressor of the engine is utilized to varythe density of the fluid in the aerodynamic torque converter and therebyprovide a variable drive without the use of high speed gearing.

Among the objects of the invention are to provide a gas turbine engineof the free power type which is selec-tively connected with anaerodynamic torque converter to provide selective and variable drive ofthe output shaft.

SUMMARY OF THE INVENTION DESCRIPTION OF THE DRAWINGS FIG. I is aschematic diagram of a gas turbine with aerodynamic torque driveembodying the invention.

FIG. 2 is a curve of efficiency versus speed and torque versus speed.

DESCRIPTION Referring to FIG. 1, a portion of the output ofa compressor10 inthe form of compressedair flows through afluid line 11 to combustor12 of gas turbine 13 which by a shaft 15 and a second stage 16 to whichthe exhaust gases of stage 14 are'directed. The exhaust gases from theturbine 16 flow through line 17 to the atmosphere.

An aerodynamic torque converter 18 is provided and has a casing with aninspect rotor 19 and an output rotor 20 that is connected by a shaft 21to the turbine stage 16. The casing is adapted to be filled withcompressible fluid, namely, air, from the compressor 10 so that uponrotation of the rotor 19, the flow of air exerts a torque which isprovided to rotate an output rotor 20 and, in turn, output shaft 22 ofthe aerodynamic torque converter. The flow of air being in the path ofthe arrows A. Output rotor 22 may be part ofa single or multi stageturbine. Torque converter 18 is preferably of the outward radial flowturbine type. As shown in the drawing, torque converter 18 comprises asingle stage of compression and expansion but the torque converter mayhave multiple stages of compression and/or expansion. Axial flowturbomachinery may also be used.

Compressible fluid in the form of compressed air may flow from thecompressor l0 to the casing of the torque converter through a firstfluid line 23. In order to control the density of the fluid in thecasing and to provide for a steady through flow for cooling, a secondfluid line 24 extends from the casing to the combustor line 1 l at theinlet of the combustor 12. V

Valves V V are provided in the lines 23, 24 to control the operation ofthe aerodynamic torque converter. In addition, valve V is provided forcontrolling the evacuation of the aerodynamic torque converter in thecase where the aerodynamic torque converter is not to be used fordriving the output shaft. Valves V V can be controlled as set forth inthe aforementioned United States patent to Hill US. Pat. No. 3,314,232to vary the density of the fluid in the aerodynamic torque converter andthereby provide for variable drive without the use of high speedgearing. When the valves V V are closed and valve V is opened, thecasing 18 of the aerodynamic torque converter is evacuated and therewill be no drive through the aerodynamic torque converter.

As shown, the turbine portion of the gas turbine engine comprises afirst stage 14 which is directly coupled to the compressor 10 and asecond stage 15 to which the gases from the first stage are fed. Thesecond stage is coupled by a shaft 21 to the input rotor 19 of theaerodynamic torque converter 18. Provision is made by gears 25, 26,shaft 27, clutch 28, shaft 29 and gears 30, 31 to permit operation ofthe work shaft 32 either through the aerodynamic torque converter. or bybypassing the aerodynamic torque converter.

Further, in accordance with the invention, the operation of theaerodynamic torque converter 19 and clutch 28 are coordinated in orderto obtain the highest efficiency. Thus, basically, the aerodynamictorque converter is utilized during start-up with the clutch 28disengaged. As the speed of the output shaft increases, clutch 28 isengaged and the aerodynamic torque converter is evacuated or, in effect,disengaged.

The aforementioned relationship can be more readily understood byreference to FIG. 2 which is a curve of efficiency versus speed ratio.Curve A represents the curve when drive is through the free powerturbine and the aerodynamic torque converter and Curve B represents theefficiency when drive is through the free power turbine with theaerodynamic torque converter is evacuated. 1

In the preferred operation, the aerodynamic torque converter is operateduntil point X. is reached in the efficiency versus speed ratio curve. Atthat point clutch shows a curve of output torque versus speed ratio thatby this arrangement, higher output. torque during start ing and reachingspeed is achieved as contrasted to the broken line curve C which wouldbe the case if only a free power turbine were used.

In accordance with the preferred method of operation of the apparatusshown in FIG. 1, it is contemplated that the valve V, would bemomentarily opened a greater amount as the aerodynamic torque converterapproaches X to thereby momentarily increase the density and lower thespeed of the output shaft to the point X so that when the clutch 28 isengaged, there will be a minimum of friction and the drive through theclutch will be smooth. The aerodynamic torque converter can then beevacuated. This method of operation has the further advantage in thatany inertia is fed to the load or output shaft rather than being lost inheat in the clutch. At the point of equal torque, the free power turbineis immediately accelerated to its maximum speed and output power istransmitted through the aerodynamic torque converter. This is achievedby declutching the clutch so that the entire drive is through theaerodynamic torque converter.

I claim:

1. The combination comprising a gas turbine having a compressor, acombustor and a turbine,

and a torque converter,

said torque converter having a casing filled with a compressible fluid,an input rotor, and an output rotor which is driven by fluid action uponrotation of said input rotor,

said input rotor of said torque converter being connected to and drivenby said rotor of said turbine,

an output shaft drive by said output rotor,

a first fluid line between the outlet of said compressor and theinterior of said casing of said torque converter,

a second fluid line between the inlet to said combustor and said casing,

said turbine having a first stage coupled directly to the shaft of thecompressor and a second stage which is not connected to the shaft of thecompressor,

the output of the gases from the first stage being directed to thesecond stage,

said second stage being directly coupled to the input rotor of thetorque converter,

and means selectivey coupling said second stage to the output shaft ofthe torque converter whereby the output of said gas turbine engine canbe selectively directed to bypass the torque converter or to operate theoutput shaft of the torque converter through the torque converter.

2. The combination set forth in claim 1 including clutch means betweenthe output shaft of the torque converter and the second stage of theturbine.

3. In an apparatus comprising a gas turbine having a compressor, acombustor and a turbine, and a torque converter, said torque converterhaving a casing filled with a compressible fluid, an input rotor, and anoutput rotor which is driven by fluid action upon rotation of said inputrotor,

an output shaft driven by said output rotor,

said input rotor of said torque converter being connected to and drivenby said rotor of said turbine,

a first fluid line between the outlet of said compressor and theinterior of said casing of said torque converter,

a second fluid line between the inlet to said combustor and said casing,

said turbine having a first stage coupled directly to the shaft of thecompressor and a second stage which is not connected to the shaft of thecompres-

1. The combination comprising a gas turbine having a compressor, acombustor and a turbine, and a torque converter, said torque converterhaving a casing filled with a compressible fluid, an input rotor, and anoutput rotor which is driven by fluid action upon rotation of said inputrotor, said input rotor of said torque converter being connected to anddriven by said rotor of said turbine, an output shaft drive by saidoutput rotor, a first fluid line between the outlet of said compressorand the interior of said casing of said torque converter, a second fluidline between the inlet to said combustor and said casing, said turbinehaving a first stage coupled directly to the shaft of the compressor anda second stage which is not connected to the shaft of the compressor,the output of the gases from the first stage being directed to thesecond stage, said second stage being directly coupled to the inputrotor of the torque converter, and means selectively coupling saidsecond stage to the output shaft of the torque converter whereby theoutput of said gas turbine engine can be selectively directed to bypassthe torque converter or to operate the output shaft of the torqueconverter through the torque converter.
 2. The combination set forth inclaim 1 including clutch means between the output shaft of the torqueconverter and the second stage of the turbine.
 3. In an apparatuscomprising a gas turbine having a compressor, a combustor and a turbine,and a torque converter, said torque converter having a casing filledwith a compressible fluid, an input rotor, and an output rotor which isdriven by fluid action upon rotation of said input rotor, an outputshaft driven by said output rotor, said input rotor of said torqueconverter being connected to and driven by said rotor of said turbine, afirst fluid line between the outlet of said compressor and the interiorof said casing of said torque converter, a second fluid line between theinlet to said combustor and said casing, said turbine having a firststage coupled directly to the shaft of the compressor and a second stagewhich is not connected to the shaft of the compressor, the output of thegases from the first stage being directed to the second stage, saidsecond stage being directly coupled to the input rotor of the torqueconverter, the method which comprises initially operating the outputshaft of the torque converter through the torque converter until theoutput speed reaches a predetermined value and thereafter operating theoutput shaft directly by bypassing the torque converter.
 4. The methodset forth in claim 3 including the step of momentarily increasing thedensity of fluid in the torque converter as the output reaches thepredetermined speed.